[llvm] LV: reuse getSmallBestKnownTC in a TC estimation (NFC) (PR #105834)

[Florian Hahn via llvm-commits]

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@@ -408,10 +408,11 @@ static bool hasIrregularType(Type *Ty, const DataLayout &DL) {
 /// the following procedure:
 ///   1) Returns exact trip count if it is known.
 ///   2) Returns expected trip count according to profile data if any.
-///   3) Returns upper bound estimate if it is known.
+///   3) Returns upper bound estimate if known, and if CanUseConstantMax.
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fhahn wrote:

```suggestion
///   3) Returns upper bound estimate if known, and if \p CanUseConstantMax.
```

https://github.com/llvm/llvm-project/pull/105834